Amidine salts of alkyl naphthalene sulphonic acids



Patented Dec. 3, 1940 UNITED STATES PATENT" OFFICE AMIDINE SALTS OF ALKYL NAPHTHALENE SULPHONIO ACIDS poration of Maine No Drawing. Application April 1, 1939, Serial No. 265,544

10 Claims.

This invention relates to amidine salts of alkyl naphthalene sulphonic acids and to methods of preparing the same.

The alkyl naphthalene sulphonic acids such as propyl, isopropyl, butyl, isobutyl and amyl naphthalene sulphonic acids are known to possess good wetting and emulsifying properties when used in the form of their alkali metal salts. We have found that amidine salts of these sulphonic acids can be prepared by methods which will subsequently described, and that these salts possess desirable surface active properties for certain fields of application. They are particularly well suited for main photographic developers and blueprint emulsions.

The amidine salts of alkyl naphthalene sulphonic acids are true addition products; that is to say, the free sulphonic acid adds on to the organic base as does any other mineral acid. We believe that this addition takes place at one of the nitrogen atoms of the amidine, which undergoes a change of valence from 3 to 5, but this fact has not as yet been definitely established for any of the inorganic acid salts of any organic nitrogen base. Accordingly, we will use the customary method of representing addition products of this nature in describing our new compounds, this method consisting simply in showing the formula of the base in juxtaposition to the formula of the acid.

The amidine salts of alkyl naphthalene sulphonic acids of our invention may be represented by the formula RIRQN cmml .HO;S.GitHu.Allr HN/ in which All; is an alkyl radical. R1, R2 and R3 are members of the group consisting of hydrogen,

alkyl, hydroxyalkyl and aryl radicals and X is a member of the group consisting of R1,

l 0:0.NR1R2 and The substituents R1, R2 and Rs may be the same or different in various compounds included within the scope of the invention, and it should therefore be understood that each symbol is intended to represent any member or the group defined. 7

An inspection of the above type formula will show that the amidine salts of our invention are salts of guanidine and its derivatives and substitution products, and particularly guanidine itself, guanylurea, biguanide, and their alkyl, hy-

droxyalkyl and aryl substitution products. These 5 compounds are all organic bases, and we believe that it is this basicity which enables them to form salts with aromatic sulphonic acids such as alkyl naphthalene sulphonic acid. Any guanidine base may be used for this purpose, such as guanidine itself, dimethyl, trimethyl, mono-, dior triphenyl guanidine, ditolyl guanidine, or hydroxyalkyl substituted guanidines such as mono-, dior triethanol guanidine'and the like. Similarly such guanylurea compounds as guanylurea itself, monoor dimethyl guanylurea, diphenyl guanylurea, tetraethyl guanylurea, and triethanol guanylurea are sufliciently strong organic bases to form salts of alkyl naphthalene sulphonic free amidine base with a solution of an alkyl 30 naphthalene sulphonic acid. We have found, however, that the cost of production of these salts can be greatly reduced by a special method constituting a feature of the invention, which method employs a salt of the base and a salt of the sulphonic acid as starting materials. This reduction in cost is due to the fact that the amidine bases are more readily prepared in the form of their mineral acid salts, such as the neutral or acid sulphate, hydrochloride, hydrobromide, etc. The alkyl naphthalene sulphonic acids are also most advantageously marketed in the form of their salts, and our improved process therefore starts with the two reagents in their most commercially attractive forms. I According to this process we mix a solution of a mineral acid salt such as the sulphate or hydrochloride of an amidine corresponding to the above type formula with a solution of a salt of an alkyl naphthalene sulphonic acid, using the salt of a metal which forms an insoluble precipitate with the mineral acid of the amidine salt. Thus for example if an amidine sulphate is used, the barium or lead sulphonate will be employed, while the silver sulphonate may be used with an amidine hydrochloride. When the two salt solutions are mixed an insoluble precipitate is formed and it is only necessary to separate the resulting compound from this precipitate by filtration, decantation or the like.

Our invention will be illustrated in greater detail by the following specific examples. It should be understood, however, that although these examples describe certain compounds constituting specific embodiments of the invention they are given primarily for purposes of illustration and the invention in its broader aspects is not limited thereto.

Example 1 One mole of isopropyl naphthalene sodium sulphonate was dissolved in one liter of ethyl alcohol and cooled to 4 C. in an ice bath. Suiiicient 50% sulphuric acid solution was added to liberate the free sulphonic acid, the acid being introduced slowly while keeping the temperature at 4 C. and the mixture being allowed to stand at this temperature for one hour. The precipitated sodium sulphate was filtered ofi, washed several times with alcohol and the combined filtrate and washings neutralized to pH=6.5 by adding an excess of guanidine carbonate. The neutral solution was filtered and the alcohol evaporated on a steam bath.

Upon complete evaporation of the solvent a yellowish brown powder was obtained which was found to be sparingly soluble in water and very soluble in ethyl alcohol. It was the guanidine salt of isopropyl naphthalene sulphonic acid and possessed definite wetting and emulsifying properties. It was also found to have good foaming properties, and was efiective as a demulsifying agent in breaking petroleum emulsions of the water-in-oil type.

Example 2 Isopropyl naphthalene sodium sulphonate was prepared from its sodium salt by the addition of sulphuric acid as described in Example 1. An equimolecular quantity of diphenyl guanidine was added to the alcoholic solution so obtained, the neutral solution was filtered, and the alcohol evaporated on a steam bath.

An oily product which solidified on cooling was 50 obtained. It ,was very soluble in aqueous alcohol, somewhat soluble in carbon tetrachloride and toluene and slightly soluble in aliphatic hydrocarbons. The solutions were found to possess definite mothproofing properties when applied to 55 woolen fabrics.

A mixed xylyl guanidine salt was also prepared by the above outlined procedure, substituting a mixed xylyl guanidine for the diphenyl guanidine. The product was obtained as a heavy syrup 60 which was soluble to the extent of about 5% in solvent naphtha.

Example 3 An alcoholic solution of isopropyl naphthalene 65 sulphonic acid was prepared by the method outlined in Example 1. An equimolecular amount of guanylurea (dicyandiamidine) was added with agitation, the solution was filtered, and the alcohol evaporated ofi. The resulting guanylurea 70 salt was a yellow solid which was soluble in polar solvents such as alcohols and possessed marked foaming action. It was also found to possess demulsifying properties when added to petroleum emulsions of the water-in-oil type in amounts of 75 .01 to .005% by weight.

Example 4 30 g. of cyanourea were treated with 100 g. of alcoholic 33% methylamine solution for 2 hours in a sealed tube at 100 C. The resultant solution was concentrated in vacuo and 300 cc. of absolute alcohol were addedtogether with a few drops of concentrated sulphuric acid. The precipitated crystals were filtered and recrystallized from a small amount of water, considerable polymerized cyanourea remaining undissolved. They were then dissolved in water and ethyl alcohol was added, whereupon 4 g. of (methyl guanyl) urea sulphate crystals were obtained. They were easily soluble in water.

The crystals were dissolved in water and reacted with a solution of isopropyl naphthalene barium sulphonate in a 5050 alcohol-water mixture. The precipitated barium sulphate was filtered off and the solution evaporated, whereby a light powder was obtained similar in appearance to the sodium salt. It was soluble in water and possessed surface active properties, and corresponded to the formula:

CHaHN NH2-C 0.HN/

Example 5 2500 g. of copper sulphate containing 5 moles of water of crystallization were pulverized and added to 1286 g. of water. 2714 g. of 28% ammonium hydroxide were added to this mixture. 2000 g. of dicyandiamide were then introduced with thorough agitation and the mixture was placed in a pressure vessel which was closed and heated for 8 hours at 103 C.

The contents of the pressure vessel were then filtered and washed with water until substantially free of copper and the wet filter cake was added to about 14 liters of 10% sulphuric acid. The mixture was heated to 80 C. to insure complete solution and was then filtered. 0n cooling, crystals of acid biguanide sulphate were obtained which were substantially pure and free from copper salt. A yield of 1200 g. of pure material was obtained.

One mole of the barium salt of isopropyl naphthalene sulphonic acid was dissolved in 500 cc. of ethyl alcohol and a corresponding amount of the acid biguanide sulphate, also dissolved in alcohol, was added. The mixture was agitated and the precipitated barium sulphate was allowed to settle and filtered off with suction, and the filtrate was washed several times with 50% ethyl alcohol solution.

The combined filtrate and washings were evaporated to dryness on the steam bath whereupon the biguanide salt of isopropyl naphthalene sulphonic acid was obtained. It was a brown powder, readily soluble in alcohol, and possessed definite surface active properties. It was found to be a good emulsifying agent for preparing emulsions of the oil-in-water type, and to have a definite demulsifying action on emulsions of the water-in-oil type. It corresponds to the formula:

ous methylamine; the solution was placed in a pressure bottle and heated in a water bath at 92-94" C. for hours. The reaction product was cerise colored; it was suspended in water, filtered In a manner similar to the preparation of monomethyl biguanide sulphate diethyl biguanide sulphate was obtained from diethylamine, except that in. this case the compound was obtained in beautiful large crystals on dissolving'the copper compound in sulphuric acid, and the addition of alcohol didnot have to be resorted to. The formula of this material is:

Isoamyl naphthalene sulphonic acid was converted into the barium salt by neutralizing with barium hydroxide. This salt was reacted in alcoholic solution with alcohol solutions of corresponding quantities of the-two alkyl biguanide sulphates, using the'procedure outlined in the preceding example. The resulting products were light brown powders, very soluble in alcohol and sparingly soluble in water.

Example 7 84 g. of dicyandiamide, 111 g. of copper sulphate (51-120) and 2'72 g. of 25% aqueous solution of dimethylamine were mixed and put in a pressure bottle. The mixture was allowed to stand at room temperature for 2 days and then was found to have converted to the pink copper salt of dimethyl biguanide sulphate. No liquid was left in the bottle. The solid reaction product was suspended in water, filtered and washed in a Buchner funnel. The wet filter cake was dissolved hot at 80 C. in 600 cc. of 10% sulphuric acid and the hot solution was filtered to remove accidental impurities. On cooling dimethyl biguanide acid sulphate crystallized in shiny crystals.

The crystals were dissolved in ethyl alcohol and reacted with an alcoholic solution of the barium salt of isobutyl naphthalene sulphonate, using the procedure described in Example 4. A light brown powder was obtained which was fairly soluble in alcohol.

Example 8 84 g. of dicyandiamide, 111 g. of copper sulphate (51 120), 110 g. of n-monobutylamine and 100 g. of water were mixed. On mixing the first three components considerable heat was evolved and the mixture became dark bluish-black, stringy and almost resinous and so stiflf that it could hardly be stirred; thereupon the water was added. The cool slurry became reddish. The mixture was heated in an open beaker in a water bath for 4 hours. The copper salt so obtained was suspended in water, filtered and washed with water. whereby 300 g. of salmon colored moist filter cake were obtained.

In order to otbaln the salt in solid form the copper compound was suspended in water and hydrogen sulphide was passed in until all the copper was precipitated as copper sulphide. After filtration and evaporation in vacuo at 40- 60 C. the butyl biguanide neutral sulphate was obtained as a waxy material in the form or scaleswith a nacreous luster.

The monobiguanide salt of isopropyl naphthalene sulphonate was prepared by reacting an alcoholic solution of the sulphate with an alcoholic solution of the barium salt or the wetting agent. A light brown powder was obtained, which was soluble in alcohol, but only very slightly soluble in water.

Example 9 210 g. or dicyandiamide, 310 g. of copper sulphate (51120) and 480 g. technical dibutylamine were mixed in the order given, a green thick mass resulting. It was placed in a pressure bottle and heated in the water bath at 96 C. for 7 hours. The dark green color changed to a dark red. The solid mass was suspended in water and filtered and the filter cake was then suspended in denatured alcohol in order to remove remaining dibutylamine which could not be removed by a water washing alone. The alcoholic filtrate was a dark bluish-black. After a second alcohol washing a very clean looking rose-colored copper salt of dibutyl biguanide was obtained.

The copper salt was suspended in water and hydrogen sulphide introduced, the copper sulphide was filtered off and the water evaporated in vacuo at 40-60 C. The resultant pasty mass was finally dried in a desiccator where it solidified entirely to fiat crystals of dibutyl biguanide sulphate having a slightly yellowish tint.

The diamyl biguanide sulphate was also prepared by the same method.

The barium salt of n-propyl naphthalene sulphonic acid was prepared and dissolved in alcohol. The dibutyl and diamyl biguanide sulphates were reacted with separate portions of this solution, the barium sulphate filtered off from each, and the salts obtained by evaporating the alcohol on a steam bath. The two products were similar in characteristics, being light brown powders only slightly soluble in water but very soluble in ethyl alcohol.

Example 10 210 g. of dicyandiamide, 310 g. of copper sulphate (5H2O) and 330 g. of monoamylamine were mixed in the above order and the mixture heated on a hot plate. The initial mixture turned dark blue with evolution of heat and then reddish purple, and finally became a molten mass. The material was mixed with water, filtered, and then twice suspended in alcohol and filtered. The rose colored filter cake was suspended in water whereupon the copper was precipitated with hydrogen sulphide, filtered off, and the filtrate evaporated in vacuo at 40-60 C. The

monoamyl biguanide neutral sulphate was ob-' tained in white waxy crystals.

The crystals were dissolved in alcohol and reacted with the barium salt of isopropyl naphthalene sulphonic acid as described in previous exam-pies. The resulting product was a light brown powder which was slightly soluble in water and very soluble in alcohol.

Example 11 84 g. of dicyandiamide, 111 g. of copper sulphate (5H2O) and 92 g. of monoethanolamine were mixed. Considerable heat was evolved. 100 cc. of water were added and the beaker set on a hot plate (low) for several hours until the mass appeared uniform. It was then poured into 1400 cc. of water. The slurry was filtered and suspended in water, the copper precipitated with hydrogen sulphide and the solution evaporated in vacuo at 40-60" Cg Lustrous crystals of monoethanol biguanide neutral sulphate were obtained.

The acid sulphate is obtained by dissolving the copper salt in a 10% sulphuric acid, removing the copper with hydrogen sulphide and allowing to crystallize by slow spontaneous evaporation.

The ethanol biguanide salt of isobutyl naphthalene sulphonic acid was prepared from the corresponding barium salt by the procedure outlined in the preceding examples. It was a light tan powder, very soluble in alcohol and slightly soluble in water. It was 'found to have emulsifying properties and also to be a good demulsifying agent for petroleum emulsions of the waterin-oil type. Example 12 A mixture of higher aliphatic aminescontaining alkyl groups of 16 to 18 carbon atoms was mixed with copper sulphate (5H2O) and dicyandiamide in the ratios of III/2:1, the amine being reckoned for calculation of quantities as Cm. The procedure was to melt the amine and add the powdered copper sulphate with stirring. A pasty blue-green mass was obtained. Then the dicyandiamide was incorporated by kneading and the completed mass warmed in a water bath. The mixture was transferred to a stoppered bottle which was heated in aboiling water bath for 8 hours. The color of the mixture had changed to a deep rose-violet. The long chain alkyl biguanide acid sulphate was obtained by introducing the material into a 10% sulphuric acid solution. It represents a white fluffy material whichhad strong foaming tendencies even in acid solution. Obtained in this way, however, it is adulterated with some unconverted amine.

In order to produce the pure compound the excess alkyl amine is removed from the rose-violet reaction product by extraction with ether. After such a removal of the unconverted amine the copper salt can be converted to the acid sulphate by introduction into 10% sulphuric acid or to the neutral sulphate by suspending it in water and removing copper with hydrogen sulphide in the customary manner.

- Inmany cases it is advisable towork with a considerable excess of amine which due to its low melting point serves as an excellent medium in which to carry out the reaction. The excess is recovered in the ether extraction and is therefore not lost.

The mixed higher alkyl biguanide sulphates prepared by the above procedure were dissolved in alcohol and reacted with an alcoholic isopropyl naphthalene barium sulfonate solution by the procedure described in Example 4. After filtering oil the precipitated barium sulphate the filtrate was; evaporated to dryness and the substi tuted biguanide salt obtained as a light tan, waxy material which was soluble in alcohol but practically. insoluble in water.

Example 13 per. precipitated with H28 and filtered ofi, and the acid sulphate formed by addition of concentrated sulphuric acid. It was separated from RIRIN in which Alk is an alkyl radical, R1, R2 and R3 are members of the group consisting of hydrogen, alkyl, hydroxyalkyl and aryl radicals and X is a member of the group consisting of .HOaSCmHaAlk 2. Salts of alkyl naphthalene sulphonic acids of the formula RiRaN C :NRa

HN .HOaS.C ioHg. Alk

CzNRs RiRzN in which R1, R2 and R3 are members of the group consisting of hydrogen, alkyl, hydroxyalkyl and aryl radicals and Alk is an alkyl radical.

3. Salts of alkyl naphthalene sulphonic acids of the formula Alk-NH C :NH

.HOaS. C xoHaAlk in which each Alk is an alkyl radical.

4. Salts of alkyl naphthalene sulphonic acids of the formula in which each Alk is an alkyl radical.

5. A .biguanide salt of an alkyl naphthalene sulphonate. v

6. A methyl-biguanide alkyl naphthalene sulphonate.

i 7. A butyl-biguanide alkyl naphthalene sulphonate.

' 8. An amyl-blguanide alkyl naphthalene sulphonate.

9.. A. method of preparing amidine salts of alkyl naphthalene sulphonic acids which comprises'mixing a-solution of an amidine sulphate with a solution of a barium salt of an alkyl naphthalene sulphonic acid and separating the barium sulphate formed by the double decomposition. a

10. A method of preparing amidine salts of alkyl naphthalene sulphonic acids which comprises mixing a solution of a mineral acid salt aikyl and aryl radicals and X is a member of of an amidine of the formula the group consisting of R R N R1,0:( J.NR1Rz and mNx LNmIu 5 with a solution of a salt of an'alkylated naph- 5 thalene sulphonic acid, which salt contains 8. EN metal forming an insoluble precipitate with the mineral acid of the amidine salt, and separating the resulting organic compound from the in- 10 organic precipitate. 10

in which R1, R2 and R3 are members of the LLOYD C. DANIELS.

group consisting of hydrogen, alkyl, hydroxy- EDWARD L. KROPA. 

